Fluid motors



Sept. 25, 1962 U 3,055,343

FLUID MOTORS Filed June 12, 1959 INVENTOR EWALD H. KURT HIS ATTORNEY United States Patent ()1 3,655,343 FLUKE) MQTURS Ewald H. Kurt, Phillipsburg, NJ, assignor to Ingersollliftand Company, New York, N .Y., a corporation of New 'ersey Filed June 12, 1959, Ser. No. 819,994 Claims. (t'jl. 121-9) This invention relates to extensible fluid motors, and more specifically to such motors adapted as feed legs for rock drills.

A rock drill having a feed leg is used for drilling holes in a substantially vertical wall of a tunnel or a mine, for reception of an explosive. The drill is of considerable weight and to aid an operator to support the weight, absorb the mass rebound and amplify the cutting force for the tool, such feed leg is added to the drill. The feed leg is an extensible fluid motor attached to the drill and having a ground engaging end. The leg receives a predetermined motor pressure when the drill is in operation.

When the drilling operation is completed, with the type of leg presently used, the leg is vented and as the drill is withdrawn from the Work, the operator must manually collapse it. Because of the weight of the drill, with feed legs of this type, Withdrawal from the work becomes a difficult operation. Therefore, if the feed leg were power retractable, the withdrawing operation of the drill would be greatly simplified as the operators hands would be free to handle the drill. Attempts have been made to use a double acting (power extensible and power retractable) fluid motor as a feed leg but these have had only limited success. It is extremely undesirable to have the second pressure line, for retraction, external of the motor connecting at the bottom of the cylinder. Further attempts have been made to provide a flow path through the motor for retraction; however, this resulted in either too great a piston head area loss, or required enlarging the cylinder beyond the desired limits and at the same time increasing the weight.

The object of this invention is to provide a double acting fluid motor with two power connections at the same end thereof without increasing the weight or size of the motor, or, decreasing the motor capacity.

Another object of this invention is to provide a rock drill with a double acting feed leg having two power connections at the same end.

These and other objects of the invention will be apparent by referring to the following specifications and drawings, in which FIGURE 1 is an elevational view of a feed leg in accordance with the invention, the associated rock drill being indicated in dotted lines therein,

FIG. 2 is an enlarged longitudinal section of the feed leg illustrated in FIG. 1,

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2, and

FIG. 4 is a sectional View taken on line 44 of FIG. 2.

Referring now to the drawings, a rock drill 2 has a handle 4 which incorporates a valve 6 for controlling the delivery of pressure fluid preferably air, to a feed leg 10. The leg 10 is pivotally mounted on a bracket 8 of the drill 2. The fluid lines extending from the control valve 6 to the bracket 8 are internal passages (not shown) in the drill 2.

The feed leg 10 is substantially formed by a double acting motor which is comprised of a cylinder portion 12 and a piston 36 having a rod 40 extending therefrom. A ground engaging member 46 is attached to the free end of the piston rod 40.

The cylinder 12 has a tubular body 14 which is closed at the end nearest the drill 2 by cap 16. The cap 16 has a center bore 18 which is counterbored and tapped from both ends as at 20 and 22. This cap 16 also has a pocket or recess 24 in the inner surface thereof which surrounds the inner counterbore 22 and is connected to the outer counterbore 26 by a plurality of drilled passages 26. A tubular plug 54 is inserted through the center bore 18 of the end cap 16 and extends into the center bore 58 of a connector 56; the connector 56 engages the threaded counterbore 20 and is retained therein. Surrounding the center bore 58 are a series of small passages 60 which extend through the connector 56. This construction of the cap 16 and the connector 56 provides a double fluid passage through the singular tubular members as will be further discussed. A tubular member or a standpipe 28 is connected to the cylinder cap 16 by a fitting 30 received in the threaded counterbore 22 which also locks the plug 54 in the bore 18.

Slidable within the cylinder 12 is a piston 36 which divides the space within the tubular body 14 into two pressure or motor chambers 50 and 52. The piston 36 has a center bore 38 which provides a sealed passage through which extends the standpipe or tubular member 28. One end of the bore 38 is counterbored to receive a tubular piston rod 40 which provides a chamber 42 to receive the standpipe 23. The outer surface of the standpipe 28 is spaced from the inner surface of the tubular piston rod 40 and thus forms an annular passage therebetween. Connecting the chamber and annular passage 42 to the motor chamber 52 are a series of ports 44 located adjacent to the piston 36. The end of the piston rod 40 receives a ground engaging member 46 which seals the end of the chamber 42. The end of the cylinder 12 remote from the cap 16 is closed by a cap and seal arrangement 32 which has a center bore 34 and provides a sealed passage for the piston rod 40.

To power extend the leg 10, the operator through the valve 6 and internal passages (not shown) connects the pressure fluid supply to the multiple passages 60 in the connector 56 and at the same time connects the center passage 58 to vent. The pressure fluid then enters the motor chamber 50 via the counterbore 20 and the passages 26 in the cylinder cap 16 to drive the piston 36 downwardly. The fluid in the contracting motor chamber 52 vents or escapes via the ports 44, the chamber and annular passage 42, the standpipe 28, the plug 54 and the center passage 58 of the connector 56.

To power retract the leg 10', the operator now connects the passage 58 of the connector 56 to pressure fluid by the valve 6 and at the same time connects the passages 60 to vent. The pressure fluid enters the motor chamber 52 from the passage 58 via the plug 54, the standpipe 28, the chamber and annular passage 42 and the ports 44. Simultaneously the pressure from the contracting motor chamber 50 vents or escapes via the multiple passages 26 in the cylinder cap 16, the counterbore 20 and the multiple passages 60 in the connector 56.

As now may be readily seen, the passage connecting the motor chamber remote from the drill which receives pressure fluid to retract the leg is now totally enclosed within the diameter of the piston rod. The passages are as close to the center of the mechanism as possible and thus the annular area subtracted from the head area of the piston is as small as possible. In this manner, the leg retracting force of the pressure fluid acting on the piston head 36 is kept at a maximum.

While I have shown and described a specific form of my invention, it is understood that various changes and modifications may be made without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. A double acting fluid motor comprising a cylinder having a pair of power connections at one end thereof; a piston movable in said cylinder and having a through bore; said piston dividing the space within said cylinder into two motor chambers; and a tubular member connected to the said one end, extending through the bore and in communication with one of the said power connections and the motor chamber remote from the one end, the other power connection communicating with the other motor chamber.

2. A double acting fluid motor comprising a cylinder having a pair of power connections at one end thereof, a piston movable in the cylinder and dividing the space therewithin into two motor chambers, the piston having a through bore, a piston rod connected to the piston and extending through the end of the cylinder remote from the one end, the rod having a chamber with at least one opening to the motor chamber on the side of the piston remote from the one end, a tubular member connected to the One end and in communication with one of the power connections and the rod chamber to provide communication with the rod chamber and its opening from such power connections to the motor chamber remote from the one end, and the other power connection communicating with the motor chamber adjacent the one end.

3. A double acting fluid motor according to claim 2 in which the rod chamber opening is adjacent the piston, and the tubular member is spaced inwardly from the rod in the rod chamber to provide an annular passage from the rod chamber adjacent the end of the tubular member to the rod chamber opening when such member extends past such opening.

4. A feed leg for a fluid powered tool including a cylinder having an end portion; said end portion being connectable to said tool and having power connections therein; a piston movable in said cylinder and having an axial bore; a hollow rod extending from said piston through the end of the cylinder remote from said end portion; a ground engaging member mounted on and closing the end of said rod; a tubular member communicating with one of the power connections extending through the axial bore and received in said rod, said rod having at least one port therethrough connecting the interior thereof with the interior of said cylinder on the side of the piston remote from the power connections.

5. A power extensible-power retractable fluid motor comprising a cylinder, a piston having an axial bore and being movable in the cylinder, a tubular member fixed to one end of the cylinder on one side of the piston that passes through the axial bore and communicates with the space in the cylinder on the side of the piston remote from the one end, and a pair of power connections at the one end adapted to receive pressure fluid, one of the power connections communicating with the space in the cylinder adjacent the one end to provide pressure fluid for moving the piston away from the power connection, the other power connection communicating with the tubular member to provide pressure fluid for moving the piston toward the power connections.

6. A power extensible-power retractable fluid motor comprising a cylinder, a piston having an axial bore and being movable in the cylinder, a tubular member fixed to one end of the cylinder on one side of the piston and passing through the axial bore, a pair of power connections at the one end adapted to receive pressure fluid, one of the power connections communicating with the space in the cylinder adjacent the one end to provide pressure fluid for moving the piston away from the power connection, the other power connection communicating with the tubular member to provide pressure fluid for moving the piston toward the power connections, the piston having a rod portion extending through the end of the cylinder remote from the power connections, the rod portion having a chamber axially alined with the axial bore to receive the tubular member and at least one port to connect the chamber to the space in the cylinder on the side of the piston remote from the power connections.

7. A double acting fluid motor comprising a cylinder having a pair of power connections in one end thereof, a piston movable in the cylinder and having an axial bore, the piston having a rod portion extending through the end of the cylinder remote from the power connections, the rod portion having a chamber aligned with the piston bore and at least one passage to connect the chamber with the interior of the cylinder, and a tubular member fixed to the one end communicating with one of the power connections and being received in the chamber to provide communication with the chamber and the passage from the associated power connection to the interior of the cylinder on the side of the piston remote from the power connections, the other power connection communicating with the interior of the cylinder adjacent the one end.

8. A double acting fluid motor having power connections at one end thereof to provide flow paths for pressure fluid from two sources, said motor comprising a cylinder having a tubular body and a wall member connected to the body at one end thereof with inner and outer ends relative to the body, the wall member having an axial bore and at least one port spaced from the bore, a connector fixed to the outer end of the wall member to provide a single connection to receive pressure fluid from two sources, the connector having a center passage communicating with the axial bore and at least one other passage communicating with the ports, a piston movable in the cylinder and having a bore and a rod portion extending through the end of the cylinder remote from the wall member, the rod portion having a chamber aligned with the piston bore and at least one passage to connect the chamber with the interior of the cylinder, and a tubular member fixed to the wall member communicating with the axial bore and the chamber to provide communication between the axial bore and the interior of the cylinder on the side of the piston remote from the wall member, and the ports communicating with the interior of the cylinder adjacent the one end.

9. A double acting fluid motor having power connections at one end thereof to provide flow paths for pressure fluid from two sources, said motor comprising a cylinder having a tubular body and a wall member connected to the body at one end thereof with inner and outer ends relative to the body, the wall member having an axial bore counterbored at the outer end thereof and at least one port communicating with the counterbore and spaced from the axial bore, a tube member retained in the bore having an end portion extending into the counterbore, a connecter fixed in the counterbore to provide a single connection adapted to receive pressure fluid from two sources, the connector having a center passage to receive the end portion of the tube member and at least one other passage to communicate with the counterbore, a piston movable in the cylinder and having a bore and a rod portion extending through the end of the cylinder remote from the wall member, the rod portion having a chamber aligned with the piston bore and at least one passage to connect the chamber with the interior of the cylinder, and a tubular member fixed to the wall member communicating with the axial bore and the chamber to provide communication between the axial bore and the interior of the cylinder on the side of the piston remote from the wall member, and the ports communicating with the interior of the cylinder adjacent the one end.

10. A double acting fluid motor having power connections at one end thereof to provide flow paths for pressure fluid from two sources, said motor comprising a cylinder having a tubular body and a wall member connected to the body at one end thereof with inner and outer ends relative to the body, the wall member having an axial bore counterbored at both ends and at least one port communicating with the counterbore at the outer end, a tube member received in the bore having an end portion extending into the counterbore in the outer end, a connector fixed in the counterbore at the outer end to provide a single connection adapted to receive pressure fluid from two sources, the connector having a center passage to receive the end portion of the tube member and at least one other passage to communicate with the counterbore at the other end, a piston movable in the cylinder and having a bore and a rod portion extending through the end of the cylinder remote from the -wall member, the rod portion having a chamber aligned with the piston bore and at least one passage to connect the chamber with the interior of the cylinder, a tubular member in the cylinder, and a tubular connector fixed in the counterbore in the inner wall end for connecting the tubular member to the wall member in communication with the axial bore, the tubular member communicating with the chamber to provide communication between the axial bore and the interior of the cylinder on the side of the piston remote from the wall member, and the ports communicating With the interior of the cylinder adjacent the one end.

References Cited in the tile of this patent UNITED STATES PATENTS 1,548,559 Simpson Aug. 4, 1925 2,068,660 Curtis Jan. 26, 1937 2,701,551 Gunning et al Feb. 8, 1955 2,754,804 Miller July 17, 1956 2,813,515 Curtis Nov. 19, 1957 2,887,092 Brady May 19, 1959 

